Values have always tended to play a central role in discourse on the environment, a tendency which is currently particularly evident in the biodiversity context. Traditionally, arguments about the environment have invoked instrumental value to highlight the necessity or utility of a healthy environment for people and intrinsic value to emphasize the importance of protecting nature for its own sake. More recently, this value dichotomy has been challenged, and the notion of a third value category – relational value – has been introduced into the political and social conservation discussion. In the field of environmental philosophy, the idea of a third category of environmental value already has a longer tradition. This article describes and compares several philosophical accounts of third-category environmental value to contribute to a better characterization of relational value and thus to a better understanding of the role this type of value can play in environmental discourse and policy.